The adhesion of different cell types to cultured vascular endothelium: effects of culture density and age.

The adhesion of lymphocytes, macrophages and resuspended smooth muscle cells to freshly subcultured bovine aortic endothelial cells is considerably greater than their adhesion to in-situ aortic endothelium when tested in vitro. Experiments with endothelial monolayers of different cell density and maturity suggest that this can be explained, at least in part, by two factors--firstly, an inverse relationship between macrophage, polymorph and smooth muscle cell (but not lymphocyte) adhesion and endothelial cell density, and secondly, an inverse relationship between endothelial adhesiveness and time since a culture became confluent. These observations may help to clarify the relationship between endothelial adhesiveness in vitro and in vivo, and to explain why leucocytes tend to adhere to regenerating arterial endothelium.